It is well known in the art to apply brackets, stops, or fenders to a roof structure in order to prevent snow that has accumulated upon the roof from sliding from the roof. The construction of the roof brackets must not only be strong enough to hold the weight of the accumulated snow, which can be considerable, but also the bracket must not damage the roof either during installation of the bracket or while the bracket is loaded while holding the snow up on the roof.
One form of a roof bracket is disclosed in Swiss patent 305,362 to Adolph Huwiler (Huwiler). Huwiler discloses a snow bracket for use on tile roofs. The snow bracket comprises a base with a generally triangular snow-retaining portion at one end and a means for attachment to the roof at the other end. The means for attachment to the roof is essentially a downwardly extending lip that hooks over a horizontal wooden roof batten used also to support the tiles on the roof. Other snow brackets, such as that disclosed in U.S. Pat. No. 625,114, similarly rely on hooks that hook over the upper end of a shingle or slate. In U.S. Pat. No. 185,137, the end of the bracket attached to the roof is provided with a hook for hooking on a nail that secures the shingle. U.S. Pat. No. 5,349,791 discloses a snow bracket that is adhesively attached to the surface of a smooth metal roof.
It has also been proposed generally to attach snow brackets by nails or spikes that are driven directly down to the subroof. This system has been used for shingled roofs, particular for asphalt and wood singles. This system, however, is not completely satisfactory. The nails extending into the subroof may compromise the weather and water seal of the roof. To solve this problem, sealant materials are applied to the upper surfaces of the brackets or the mounting nails are covered by the course of shingles above the bracket. However, sealants are prone to failure, which can then result in a direct water path from the roof top through the subroof along the nail. Covering the mounting nails with an overlying course of shingles during the initial installation of the roof is a solution. However, a similar installation on a pre-installed roof is difficult. Individual singles must be removed to expose the surface upon which the bracket is to be installed and a new replacement single reinstalled to cover the mounting nails. Short of removing a substantial portion of a roof, any removal and reinstallation of an individual shingle must be carefully done to preserve the integrity of an overlying shingle. The result is a time consuming and often difficult process.